Single-celled green algae of the type Chlamydomonas
are microscopically small organisms: ten of them
fit side by side on a human hair.

What green algae are up to in the dark

by Staff Writers
Bochum, Germany (SPX) Feb 19, 2013

How green algae produce hydrogen in the dark is reported by biologists at the Ruhr-Universitat Bochum in the “Journal of Biological Chemistry”. Hereby, they have uncovered a mechanism for the production of the gas which has hardly been examined before; usually, researchers are interested in light-driven hydrogen synthesis.

“Hydrogen could help us out of the energy crisis”, says Prof. Dr. Thomas Happe, head of the working group Photobiotechnology. “If you want to make green algae produce more hydrogen, it is important to understand all the production pathways.”

Green algae produce hydrogen under stress – even in the dark

Single-celled green algae of the type Chlamydomonas are microscopically small organisms: ten of them fit side by side on a human hair. In some ways, microalgae are not so very different from higher plants, such as trees. For example, they also perform photosynthesis. Unlike land plants, they can use light energy for the production of molecular hydrogen (H2).

“However, Chlamydomonas and co only form hydrogen under stress”, says Thomas Happe. “The disposal of the energy-rich gas serves as a kind of overflow valve so that excess light energy does not damage the sensitive photosynthetic apparatus.” Chlamydomonas can also produce hydrogen in the dark. Although this fact has been known for decades, H2 synthesis in the absence of light has barely been studied because much less of the gas is produced in the dark than in the light.

Moreover, it is complicated to isolate large quantities of the key enzyme of the dark-reaction, the so-called pyruvate:ferredoxin oxidoreductase. The RUB researchers nevertheless tackled the project.

Read more: What green algae are up to in the dark — biofuel daily.

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